My first model is a wing tip for an RC plane. The plan is print it in WSF and then fill it with 2 part polyurethane foam and then cut, hack, sand away the excess foam and then use Bondo(polystyrene?) auto body filler and sand that smooth. No, it wont fly after all that. I'll use it as a plug for an epoxy and fiberglass mold.

The question is will the Bondo melt the WSF? Will the foam distort the shape as it expands? The solidify modifier was used and it says thickness is .01 and Outer is -1.00 but I dont know what that really means. ,01 and -1.00 what?

I didnt think this thread got started and I have an almost identical one in the 3D modeling area. The main question was about units and scale and the other thread is addressing that.

The other part of this thread has to do with WSF properties and interaction with other materials. I want to use 2 part polyurethane to fill my hollow printed object to make it solid. I'm hoping the holes in the design will give the foam exit holes before it twists the object all out of shape. I've used this foam before and I'm pretty sure it wont be a problem.

The other bigger question is whether the WSF finish can handle Bondo and some sanding? I know Bondo will eat some foams but not polyurethane, so that leaves the WSF as the unknown to me.

The idea is to make a plug for a mold and this should have a very smooth finish and that's why I want to use Bondo, to get a slick finish.

Well, now the problem is clearer. The model got canceled because the wall thickness is too thin for the size. I used solidify again and submitted it and now it wont accept it. Weird, it accepts the thinner model but wont print it and then rejects a thcker model. I emailed the file, so maybe they can tell me what's wrong.